Padding File Length in MPEG Streams

Can any compressor produce synchronous, multiplexed MPEG files (program or transport) with identical file lengths, that is "padded" to be exactly the same length to the bit? I believe this can be done with Pixel Tools but I don't know how and don't have access. Can other compressors produce such padded files directly? Are there any tools that might help me add pad to an existing file?

I currently use TMPEGenc, which has always done a great job for me, but as far as I can tell, it can't do this. Three files of identical length with identical CBR settings don't come out the same length to the bit.

Cheers,
tod

Tod Hopkins
Hillmann & Carr Inc.
Washington, DC