I think I know a way to buy an inexpensive preamp with remote.
Older preamps which have analog surround sound technology go very cheap used. Heck, I sold an old. Fosgate one last year for mabe $35.00. There have been a number of similar ones on my local Cragslist prior to and since then.
Two channel folks don't tend to like multichannel preamps so I am sure you could probably find some on the giant auction site if not locally.