Got a Comcast remote?  Other Cable company remote?  You can get a Comcast new shipped on eBay for typically $6.

Assign Setup Code 31758 to the AUX button.  Then use the 994 Command to assign the following EFCs to buttons of your choice.

1    17122
2    16098
3    16610
4    15586
5    17378
6    16354
Clear    48610
Cancel    33506
Volume +, Audio Attenuator    32994
Volume , Audio Attenuator +    31970
Mute    33762
Power    32738
Video Mute    33250
Audio Mode    32226
Mode Lock    66274
Video/S-Video    65250
Front/Rear    65762
Set    64738
Memory 1    66530
Memory 2    65506
Memory 3    66018
Memory 4    64994
Input A    08930
Input B    07906
Input C    08418
Input Select 1    41698
Input Select 2    40674
Input Select 3    41186
Input Select 4    56546
Monitor 1 (input 1 out)    21218
Monitor 1 (input 2 out)    20194
Monitor 1 (input 3 out)    20706
Monitor 1 (input 4 out)    19682
Monitor 1 (input 5 out)    21474
Monitor 1 (input 6 out)    20450
Monitor 2 (input 1 out)    53986
Monitor 2 (input 2 out)    52962
Monitor 2 (input 3 out)    53474
Monitor 2 (input 4 out)    52450
Monitor 2 (input 5 out)    54242
Monitor 2 (input 6 out)    53218
Monitor 1 in/out    37602
Monitor 2 in/out    37858
Mode C    04066
Aux Audio    11490
Processor    11746
Pass Video    45794
Pass Audio    44770
Matrix    44258

This programming can also be accomplished with a JP!.3 computer interface cable.  $8 or so.