Okay I'm going to answer the original question--I have experience with limited breeding so I'll share my results with you. I too started out with one chin LOVED it so much I got others. I got a boy chin from a petstore got another boy chin from a friend and put them together. Then I found out the boy chin from the petstore was not a boy chin but in fact a girl. She ran away, no lie--she ate a whole in the screen window and ran away, and I was devastated, my boyfriend bought me another chin that looked just like her. Then my girl was found, so now I have 2 girls and one boy chin. Girls lived together, boy lived alone. I discovered in time the once boy chin was pregnant, but ALSO discovered the new girl pregnant as well--obviously I had bought her not knowing she was pregnant. So I had 2 females at the same time pregnant. Bobo and Abigail are their names. Abigail got a URI, she was very, VERY sick. I took her to the vet and told the vet I believed she was pregnant. The vet did not agree and put her on Baytril which should never be given to a pregnant or nursing chin as it affects the growth of any kits. I was very lucky my Abigail survived her illness, a URI is deadly in chins especially when they are already weakened from being pregnant. 5 days after her last baytril treatment she gave birth to 3 premature babies. Prior to this happening and I mean days prior, I crunched Gordon in the livingroom recliner. My brain said ok you lost your beloved Gordon but now you have 3 more babies to replace (a chin can never be replaced in your heart I soon learned) I thought i had it covered, lucky for me I found the forum because of what had happened to Gordon, so I knew about hand feeding babies. I assumed the babies should be hand fed because they were SO tiny. I didn't let Abigail take care of them on her own. I went out and bought everything I should, I worked 3rd shift, while I was at work my son stayed up and fed the babies every 2 hours, I came home slept for about 4 hours to give him a break then got up and took care of them until I went into work. You DON'T really know how to handfeed babies the first time you do it. You think it's important to stuff as much milk into them as possible. I KNOW I aspirated my kits, they all died within 10 days. 2 died in my hand, 1 died in my son's hand--my son who was 19 at that time crying because his little chinchilla he tried for days to keep alive did not live. Some people say, Laurie you don't know if that's what happened, they were born premature, they could have gotten Abby's URI from the cage, lots of things could have happened. BUT I believe it's because I was not prepared at all despite all I read--and believe me I read a lot. I should have waited to see if Abigail caring for them would be enough. I just assumed she was weak from being sick, I assumed they needed more than their mother's milk. A week after all of Abby's babies died Bobo gave birth to 2 kits, not premature, very healthy. Again because I did not know better I missed that one of them was constantly wet down the front, I assumed it was from milking at his mothers teet, I did not know until it was too late that he was not thriving, and again this little boy died in my hand after living 2 weeks. After he passed my son noticed he did not have appear to have a tongue. From the 5 kits I had born to me with my "limited" breeding I have one--GiGi. She is named after her father who I killed--GG for Gordon's Girl.
After Bobo and Abigail had babies they HATED each other. They could not be in the same cage together anymore. I was lucky in that I had 3 cages and separated Abby from Bobo when I noticed her sick--Bobo could have just as easily developed a URI. I tried to put them all back together--tried to see if Abby could help nurse some of Bobo's babies but that was not happening. Bobo and Abby fought and Bobo ate 3 of Abby's toes off. So two girls that once loved each other and snuggled constantly now hated each other. So Abigail had not only lost 3 babies she lost her cage mate. To this day they absolutely hate each other.
I currently have males and females. I look at them all the time and go I wonder what a baby from so and so would look like--I wonder this for about a second.
You say your wife could never give up a kit born to you, to me that sounds like she is a really loving and caring person. I've been told I am as well, which is why I KNOW your wife would be absolutely devastated if what happened to me happened to her--if you had kits born you did not know how to care for--if you didn't know how to feed properly should they need to be hand fed. I know your wife will be heartbroken if something goes wrong during the labor process and she has a mother die--or perhaps mother and all the kits die.
I think if this is something you and your wife truly want to do then be responsible and don't go into this lightly. Find a breeder near you--ask them to mentor you, ask them to allow you to visit and see kits first hand, ask them if they ever have to hand feed to show you how to do it. Ask them the true horror stories of breeding. Also if you want to know who should breed, what colors should be together, then become a member of MCBA--attend shows. LEARN about the animal you are wanting to breed albeit just for a few babies--do your homework, take some time.
After Abigail's babies died and GiGi's brother died, I attended my first chinchilla show, I've gone every year since. I am a member of MCBA I go to the seminars in my area, I met people who breed, I made friends with them, I ask them if I can come and see babies and they let me--they let me hold them and see them. I have offered my help in hand feeding, but am also terrified should the time ever come they take me up on such offer.
It's enough for me to never breed again--I love all my chins too much to see them die or to see them lose babies they carried.
So I urge you if you really want to do this, don't take a month to decide--really look into this and find and get some help and follow the Boy Scout Motto--Be Prepared before you actually go forth with it.