Have a look at this...
http://www.optecinc.com/astronomy/perseus_4-port.htm
New, 4 port, instrument selector from Optec. Would go really good on a RCOS or CDK. Wouldn't have so much hassle with changing instruments every time you wanted to use a new camera and such. However, on smaller scopes, I can foresee some balancing problems occurring, and some new back focus issues arising.
Looks a good piece of kit, though.