CPU 1 is probably best for what you need. 2 & 3 are LC's so you won't get the FPU you're looking for with them and the rest on the list are too expensive. I bought a pair of 40mhz 040's from IC-China recently and had no problems with them. It did take about 3 weeks to arrive, though, most likely due to increased security at customs.

I also found these from same seller

http://cgi.ebay.com/Motorola-68040-Processor-XC68040RC40M-02E31F_W0QQitemZ230141098167QQihZ013QQcategoryZ4663QQtcZphotoQQcmdZViewItem

40mhz! Woo Hoo!

http://cgi.ebay.com/Motorola-68040-Processor-Xc68040RC33M-00E31F_W0QQitemZ230138994740QQihZ013QQcategoryZ4663QQtcZphotoQQcmdZViewItem

33mhz

http://cgi.ebay.com/Motorola-68040-Processor-Xc68040RC33M-02E31F_W0QQitemZ230138994704QQihZ013QQcategoryZ4663QQtcZphotoQQcmdZViewItem

Another 33mhz

You're not going to see any speed increases unless you overclock the motherboard, though. Even if you don't overclock, the higher rated chips will likely run cooler at slower speeds and probably last longer and you'll have more room to play around if you do decide to increase the clock rate one day.