That will probably be me in a few years. I already start a lot of more complex seeds, such as trees and shrubs, medicinal herbs, perennials in addition to the much easier vegetables. And I did start growing Citrus from seeds. So far, I've started Flying Dragon, Yuzu, Dunstan, Ichang lemon, and Kiku daidai. That last was a bonus seed packet someone sent me - I had to look that one up. It's a fairly hardy sour, bitter orange-like citrus, not considered edible, but grown in Japan to a small extent. And it is known to hold fruit for several years.
I will also soon have some citrandarin (852) seeds to try.
I do have a greenhouse under construction that should be done before the coming winter, so I'm hoping to have an environment to overwinter some plants. But that's not the ultimate goal. I would want to grow as much as possible outside, as long as the protection requirements are not too overwhelming. I'm sure I can wrap some trees in Reemay fabric and string up some Christmas lights. Lots of options, and still finding out what works for my situation.
Breeding some Citrus and trialing them outside, yes absolutely. I do find myself thinking about which ones I could use as parents and how to scale up my operation to accommodate trialing as many seedlings as possible. I don't think I could ever grow 20,000 as we've read about in Kumin's thread, but then I'm in zone 8, theoretically, with once-per-decade drops under 10 F that technically are zone 7b winters. That's in Duvall, Washington, east of Seattle up at 550 foot elevation. And with a good choice of parents (with zygotic seeds?), and not quite as demanding a cold tolerance, maybe a mass selection experiment is more feasible in a field not much bigger than an average vegetable garden. I'm thinking about it, but I have a lot to learn in the meantime.