I must have fallen a sleep and missed this little thread? - lol. Sorry bud !

The BSC621-2 C/Ku LNBF, as you know, is a great LNBF which delivers both C & Ku Band signal on 1 cable. The problem is that you can not distribute more than 1 signal to 1 receiver independently. So as I look at it you have 3 options:
1. You can do your loop-through with limitations. You should NOT be able to place a DiSEqC switch as you suggested because the BSC621-2 uses DiSEqC switching to switch between C-Band and Ku Band. (Not the option I would do)
2. Use the A/B switch as you have been. You can get remote ones. (This option may not be the best, however it may work the best depending on your setup and what kind of video output you wish to have on each TV)
3. Only use 1 receiver. Use Component or HDMI for TV 1 and output composite cables to a RF modulator and run RG6 to the 2nd TV. You can then either input the coax into the TV or run it through a VCR(de-modulator), and then input composite cables into that 2nd TV. (This option may not be the best if it is difficult to run a cable from TV 1 to TV 2 and would not give you the best picture option) I would also suggest a remote extender to control the receiver at TV 1. If the distance is not that far between the TVs, there are "splitters". For instance - You could use a HDMI splitter after the receiver, running a HDMI feed to each TV.(If this is possible, it would be the best option working with what you have) The only better option would be option#4(see below).

Thinking outside of the box(Option#4): You could replace the LNBF with a Dual output C-Band LNBF. This would give you the flexibility to run 2 cables, 1 to each receiver, but NO Ku Band. Don't you have another Ku Band dish anyway? One receiver could run the Ku Band Dish and the other could run the C-Band Dish.