Hey man it seems from what you want production wise you would like a 303, but unfortunately it is an SP without a native battery power component (however there is something on the forums about converting it so it has one!). 202 could have fit the bill but it has an awfully small amount of space, so a 404 seems like a good choice. I have had little experience with the SX but imo I think the original 404 has better sounding effects. Others options I've seen on this forum include the su-10, su-100 and qy100 by Yamaha although those were discussions about sequencing

You could easily battery power the 606- it only needs 9V and 1000ma. I bought this and it works great:
http://www.ebay.com/itm/360507624892

Need the adapter to make it work for size or polarity I forget- MUST be center pin negative whatever you do-
http://www.ebay.com/itm/NEW-Godlyke-Pow ... 25687a8624

SP-forums- Thread on the topic where I learned about it:
viewtopic.php?f=13&t=13890&hilit=battery&start=0

Also 202 is very limited I got one and you cannot resample thought it has other cool features but just my input on that.

Alternative to battery pack is just plop some money down on a cheap android tablet and get some software for it, like Caustic or something. I think they got an MPC cloney thing for it too...

If you want real knobs/pads, better go with that battery pack.

Just buy a 404 and be done with it. After you buy the 303 and make/buy a battery pack it will be more expensive and more shit to haul around than just buying the 404 to begin with. Besides, you get 32 sounds maximum on the 303 and 120 sounds on the 404. If you're using it while out and about chances are you're not going to have a memory card reader and computer nearby to back up/swap your save files. Also if you buy the 404 you can at least use the compact flash cards from the 606 without needing to buy expensive smartmedia cards (202/303).

Like HS said, another practical option is to buy some sort of tablet. I use my iPad Mini and a USB audio interface while I'm on the go. 8hr battery life and limitless possibilities!

microsampler

keyboard, can pitch and timestrech, good effects, fun sequencer, easy to sample too...regret selling mine. Cheap, and more versatile than a 303 or 404 just due to pitch and 2 track sequencer... on the negative side, not a ton of sample time per "set" but you can load at 22khz and get grit and more room.

it's the kind of gear that is sort of overlooked, but if it had some star cred like j-dilla/flying lotus and the 303 people would be drooling over...

I currently have a decent collection of battery powered gear, but I'm feeling the portability of my Note 3 and Caustic 3. The battery life on that phone/tablet is unheard of. The SP404sx battery life is probably the longest lasting of the 6xAA machines I have (excluding the Monotribes). If you got the money, check out the OP1.

Ya Caustic is pretty cool- like Reason for Android. Too small on my HTC Amaze though but it is very powerful and full featured.

I got that battery pack and I also got rechargables for my SX but one thing I dislike about the rechargables is once they begin to die they die FAST. Reg batt on the SX will show low batt blinking for what seems like 30min before the unit actually shuts off but rechargables it feels like only a couple of mins. Still saves money over reg batt if you go that route.

C