My plan is to finish all the commissions I've agreed to, with a moratorium on new ones. Upon analysis, of the companies I'm currently working with, there's one in particular that commissions a whole bunch of $35-40 color quarter pagers, which are eating up a great deal of time to rather minimal profits, so once my current assignment with them is done, I'll tell them I can't continue to work for those prices--hopefully we can part amiably, but it's just not worth it to spend a day and a half of my life for $35 bucks and a publishing credit with a company that I've already got credits with, particularly when I could spend a day and a half on an original and make several times that. (And there's always a chance that they'll raise their prices!) (Okay, no, there probably isn't.)
When those are all done, and depending on the time of year (i.e. January and February are always death) and the schedule of those companies that it IS worth my while to keep working with, I'll take between one and three months and pursue my own art aggressively. Then I'll see where I stand. If I decide to re-open private commissions at that point, I'll hike the prices significantly--$350 to start, and if my schedule starts filling up again, I'll start heading into those scary realms that Ruggels was speaking of. *grin*
I want to thank y'all for your great input--since the profitability of art is defined by the sum of your friends and fan base, I really appreciate the advice from everybody. It's one thing to have your husband and a few close friends telling you you're underpriced--it's another to have forty or fifty people say the same thing! Thank you all!