Hello!
I used to always hardwire both ends of cables into my gear. Can't beat it sonically and it's cheap! Total pain in the butt to swap stuff though. Since I started doing a lot of equiptment swapping (for testing gear) I have not hardwired anymore.
I have not tried the smb's although I have seen them in catalogs so they can be obtained fairly easily I think. Check out digikey, newark, mouser and places like that. XLR connctors are pretty decent and better than most any (and maybe all) rca's from a signal connection point of view. They are cheap because they come from the pro audio world - not from the 'hi-end $$ audio world'. I have had guys use xlr's wired single ended for connectors for this reason - not a bad plan if you diy your own cables and can mod the amp / source ends of your gear.
Levinson tried to use a Camac (SP?) connector instead of rca's some years back but what happened was everyone was using camac to rca converter's - which is far worse than just an rca so they gave up on that. It was not possible for most folks to get camac ends on cables - unless they used cables made by levinson.....
The best from a connection point of view that allows some flexibility is to hardwire one end of the main cables in and out of the pre-amp. This means you have to comit to a flavor of cable though.... This is basically our hardwired cable option - typically using a favorite cable you send on up but I also can make a cable if you don't have a favorite.
For max flexibity in a multi-input pre-amp hardwiring some cables and having some rca connectors for alternate inputs and outputs is not a bad way to go.
Many Thanks and Happy Hollidays!
John Chapman
www.bentaudio.ccom