I'm kind of late in getting back to everyone, but thanks to all the great input! It really gave me a lot to think about.
I have to admit to being totally shocked that so many people (I've also asked on other forums) are opposed to double-sided prints. There's got to be a psychological thing to it. For me it would save me a TON of money on printing to do a large order of double sided prints instead of two smaller, separate orders for two different illustrations. I figured this would be okay since if people liked both sides of the print, they would either A) be satisfied that they got two for one or B) buy a second copy of that print so they could have one copy for each side. That seemed fairly logical to me since if I were to sell these prints separately people would have to buy two prints anyway to get both illustrations.
I think people feel like they are getting cheated if they have to buy the same thing twice, when really it's the same thing as if they were already separated... and I thought people would be able to see that, but my research has shown that that is absolutely not the case. It looks like I am really going to have to reconsider my double-sided prints idea, because most people aren't wired that way, haha. Rats.
As for everything else, I appreciate all the thoughts and comments. All of it has been really useful.
If anyone else wants to add to this thread, go for it! I'm still trying to figure out what to do, anyway.