Another way would be to outsource the tuners (eg use it with a linux NAS, Seagate Dockstar or other system) and use the adapter via network (the driver has full network support integrated, server and client), that way the tuner can be decoupled from USB on the VU+ (and also be used from other systems eg. windows in your network).
Am I reading this right when I think that would allow one tuner to be used on both a Vu+ and DM500hd without having to switch? Of course not simultaneously.