Yes, I have dealt with Sipsey River in the past and wouldn't be afraid to buy a used bow from them. Like Arthur said, although your plans right now is to getting something you can hang on to and shoot for a long time to come sure might change. I'd still say to get something in the 45 pound at your draw range. You may loose and inch or so of draw though as compared to your compound. You may want to take that into consideration. Most bows are measured at a 28" draw. If that is the case I'd stick in the 45-50# range at 28". Other then that, I would not be afraid to pick something older up. There are a lot of older Bears out there that can still shoot. A lefty may cost a little more though. We paid probably an extra $50 for the lefty Bear Hunter that my son currently shoots.
If you want to go the custom route, I would consider the Falcon (like Art mentioned), or the King's Pawn, both by chek-mate, and both FF ready. I personally own a King's Pawn and I'm very please with it.