I also want to but another Alesis kit to use as an add-on for my DM10X Mesh.
So far I'm thinking along these lines. The list is in order of what I would currently prefer and is dependent upon how much I'll be able to spend when the time comes.
Command Mesh - I like the idea of adding one more 10" mesh pad, three 8" Mesh tom pads, and the added 8" Bass Mesh and the smaller cymbals for placing in various places around the rack. The main consideration of this one is the ability to add custom samples
Surge Mesh - Same as above but with a cheaper module. Is this module any good? If not I'll get a MIDI IO asap
Sample Pad Pro - I like this thing, and if I get one of these, the sampling abilities of the Command would become less of an important decision.
I love what I've seen of the Strike so far. I just don't (yet) want that large of drum pads. I love the ones that I have and, like I said, I'd love to add some smaller 8" dual zone mesh! I get the feeling that there's a LOT more going for the Command module over the Surge than just adding custom sample ability. For one, I bet the included sounds are a lot better. For another, it might even be able to assign custom MIDI notes to the pads, so I could just MIDI them over to my DM10 kit, which I would really like to do above all else.
Grabbing another DM10 or DM10 MKII Pro would be cool too, but I wouldn't get the smaller pads unless I went Studio. But if I went MKII, I think I'd like to try that Pro module.
Just some of my thoughts at the moment.