Programmable D-to-A converters? (self-changing channels)

Any Digital to analog converters (set-top boxes) that can be programmed to change channels at set times?

That feature would come with a DVR. Echostar is going to sell a A to D set top box with DVR in the near future called the TR-50. It has two tuners and is a HD box as well. See attached pictures.

I think there will be some need for this capability to be provided in a converter box as well. I remember having this capability in STBs as far back as 1990; you'd set your VCR to record Channel 3 from 8PM-9PM and also set your STB to switch to Channel 24 for 8PM-9PM. The capability would be used for a similar purpose now, to extend the life of existing DVRs and DVD Recorders, which up until now were able to switch (analog) channels themselves, but now will need to rely on a d-to-a converter box.

I have no idea if there will be a big enough market, though, for this capability, to substantiate offering boxes with the capability.

Dish Network ViP211 has this capability. I use it in conjunction with my TiVo to record SD widescreen versions of HD programs on my TiVo. Tivo changes channels 1 min before hour (Tivo cannot control HD channels on the 211), 211 changes on the hour and records the HD program.

Not looking for a $500 DVR. I already have Super and Digital VHS videocassettes for the purpose of recording (and more importantly, storing) television programs. I remember having this capability in STBs as far back as 1990; you'd set your VCR to record Channel 3 from 8PM-9PM and also set your STB to switch to Channel 24 for 8PM-9PM.

This is what I need.