First time I'm contributing something useful to the forums.. been a long time lurker.
So I live in central NY and there are just two radio stations... krock and kiss fm... I got pissed one day from all the britney news so I decided to get sirius. I hated the mounting options and my first stab at making a custom cupholder mount was disastrous. Like all cupholder mounts, I had to reach above or around the gear shifter to change the stations. I need something that was offset from the cupholder and I also wanted to use the cup holder as well. So here's the pics of what I ultimately came up with..

From the driver's view, I can see the sirius radio without having my vision leave the road that long since the gear shifter is not blocking anymore.

A low shot showing my cell phone in the cupholder and the design of the offset.

On the back, I glued a wire holder thingy to keep all the wires neat. Next step is to fine some wire loom and zip tie all those wires into the dash opening. The funky yellow stains are from the gorilla glue I used. Stuff is strong!

From the top, in case anyone is wondering how all the pieces fit together.
Construction...
In case you wanted to try to make this yourself, I'll go through some of the steps I took. Sorry I couldn't take pictures during the construction, there was a lot to juggle and I couldn't hold the camera.
Cupholder - Outer diameter = 2 7/8" fits like a glove. Inner diameter = 2 1/2". The wooden cupholder is tapered from bottom to the top to provide a wider gluing surface. I used some spare 2x4 wood I had lying around.
Offset mount (thingy) = made of hardboard (same material as those brown clipboards). I glued 3 layers and clamped them overnight. Like I said before, this stuff is STRONG! Wear gloves... and follow the directions.
Metal bracket - I had a spare GPS antenna that had one of those inside suction cup mounts to place on the rear window. I took the suction cups out and basically mounted it upside down.
Sirius Radio and Dash mount - stock with original purchase. Had to fiddle with the right angle to ensure I could view it easily from the driver seat.
Other tools - screws, Gorilla glue, 2 1/2" hole saw, rasp, hand saw, hot glue gun
Total cost = $12.97 (tools I didn't have) and 4 hours of work (not counting drying time)
General steps -
1) Cut out 2 1/2" hole in 2x4 wood.
2) Use hand saw and rasp to get into cylindrical shape. Repeat for 1 more.
3) Glue two cylinders together.
4) Glue three layers of hardboard together. Let everything cure for at least 2 hours.
5) Cut out hardboard mount using a template with hand saw and rasp.
6) Seal cup holder and glue hardboard mount with raised platform (also hardboard, 6 layers total at the highest point) Let dry.
7) Glue all parts together. Drill 3 holes for the metal mount. Screw mount to hardboard base.
8) Go to car, and hot glue wire holder to the back. Find good position, take off the red tape on the dash mount. Stick to metal bracket. Optional, you can add hot glue to places that are recessed. GPS mount had a center recess for the antenna screw.
9) Hook up wires, stick cell phone in your new cup holder mount.




My fiance thinks I'm crazy, but I love it.