Yamaha DTXpress/DTXplorer/DTXtreme

hello
my name is alex and im currently looking into getting the Yamaha
Dtxtreme IIs kit. 
Is there anywhere in the uk that sells it besides
www.wembleydrumcentre.com ?
One of the reasons im interested is the midi capabilities of the module. 
Is it possible to, for example, trigger midi chords of the rim of a
tom pads, while the rest of the pads trigger regular sounds?
I was also wondering about the sampling capabilities of the Dtxtreme,
as there does not seem to be too much internel memory.

thanks very much for you time
alex