Yamaha DTXpress/DTXplorer/DTXtreme

Hi Guys...  I bought my first e-drum set back in July...  A DTXpress 
II used of of e-bay...  I have to tell you guys I love it...  I've 
been a hobby drummer for 20 plus years and for me its the greatest 
thing since sliced bread...  I have played my acoustic set exactly 
once since I got my e-drums...  I really dig these things...  I am 
having a blast creating custom drum kits...  I realize there is a lot 
left to learn about this stuff...  

I'm also begining to catch the upgrade bug...  I've added two cymbals 
to my kit by using the 9/10 input split into a couple of triggers I 
robbed from an old "DrumFire" machine I have...  Took a couple of old 
splash cymbals and completly wrapped them in duct tape securing the 
triggers inside...  I have to tell ya they work great and the price 
was definitly right... The mass quantity of duct tape cuts out any 
cymbal noise and I use them just for crash cymbals so there is no 
worry about stick response...  

My questions are these:
1) Is there any way to add more triggers to my set up ?? Do any of 
the other inputs work like 9/10 ??

2) Does anybody know of a place in the Los Angeles area that stocks 
parts, clamps, pads etc... for the DTXpress series ??  I know there 
are places that sell online ie; Midwest Percussion & Drumbalaya but 
I'm looking for a walk in type store...  I like to browse...

Thanx I appreciate your time....
Dennis....