Hi Steve,
This is 10mm in width (the same as your spacer) but requires 36mm unmounted filters - not sure if that is a problem for you.
http://www.teleskop-express.de/shop/...low-profi.html
Otherwise have you considered the dslr clip in filters? eg
http://www.bintel.com.au/Astrophotog...oductview.aspx
Cheers
Russ