I just won...

... this.

(if you can't see it, it is a used EOS mount Sigma 400mm f/5.6 APO Telemacro HSM)

I got a pretty decent price ($290 + $15 S/H) especially since there is a decent chance it doesn't have the Err 99 incompatibility. Even if it does, it is still a decent price for this lens, since the HSM is quite rare and the condition seems good.

I'll be selling some lenses to cover the cost, including my Sigma 600mm reflex (once I'm satisfied the new lens is better).

More details soon...