Same here - anytime my wife and I are somewhere without a Tivo, she's bugging me to fast-forward through commercials.

I've got one of the Series2 Tivos with the integrated DVD burner, but I actually have hacked my Tivo to add some functionality:

* Uncrippled transfers from the Tivo to my PC (the Tivo normally encrypts TivoToGo downloads, which results in transfers of around 0.8MB/sec). I can download at 1.9MB/sec. On the PC, I can chop commercials and then output to DVD much faster.
* Added a webserver so that I can access/control the Tivo from anywhere, in case I want to record something - no mucking around with Tivo's online scheduling too.

With older Tivos (ie, your Tivo service number starts with something <5), this can be done by taking the Tivo hard drive and putting it in a PC with a special linux boot CD. With newer Tivos (including current Series2.5, Series3/HD), you have to unsolder and reprogram a PROM.