pre-recorded reel to reels

Last year I purchased a RT707 reel to reel deck. I have been buying pre-recorded reels from a company called "Irvington Music". Coes anyone know of any other places to buy pre-recorded reels?
There are many for sale at EBAY, and you could post wanted ads in Audiogons music section.
Estate sales can also be a good bet. I would highly recommend, though, that you try to find a good used Dolby B decoder, as the pre-recorded open reels recorded with Dolby B are far superior to those recorded "flat". Your best bets are an Advent (though you have to be sure it works--there were long term reliability issues with the unit) or a Teac. You ought to be able to find them cheap. If your tastes run to classical music, you'll want to try to get Barclay-Crocker copies of tapes--they're truly outstanding, though they were generally recorded with the polarity reversed. I still have a large collection of these old opoen-reel tapes, and I love them.