Yamaha DTXpress/DTXplorer/DTXtreme

hi there 
- my first post searched through 
the archives & couldn't find my question. 
i'm actually a guitarist 
that likes to play drums when ever possible.

i've been thinking 
about putting together 
an electronic drum kit for a few years now.
the drummer in my band 
is using the D-Drum module and triggers
and replaced the original skins with mess heads.
sounds great-nice to play but 
the price is  a bit terrifing to my wallet

i like the mess head idea together 
with the look of real drums.
i will probably buy a cheap peice of 
junk 4-5 peice kit 
and change to mess 
heads and d-drum triggers. 

the module/interface is the 
bit of kit i'm not sure about.
sounds of the module 
are not really important and as far as quality
probably will not compete,as the 
computer will provide the sounds 
(DrumkitFromHell superiour or B F D)

important is: 

1. standard midi in/out ports.
2. a good control of the velocity parameters.
3. and of course price. :)

so if you have done a similar thing,  
please post any suggestions.

thanks

phil