Killer!!! That's a wonderful poster with autograph!
No I didn't get out to Botcon '07. I plan to go next year before TF2 hits theaters.
I saw it as an opportunity to get one of those one-of-a-kind things and I don't see Cullen items too often offered, or they are autographed on opened toy packages. When I saw that this was a hand sketch of Optinus signed by Don as well as Cullen I knew I wasn't going to see that again, so I jumped at it hoping it was going to look nicer than that blurry photo on the auction.
I just received it today. Professionally framed and looks beautiful! It's in about a 12x16 frame estimated. Drawn in permanent inks:

Very happy with it! I hope next year when I can afford to go to Botcon '09 I will get to meet Cullen in person and get a picture with him. That would be awesome.