I'm thinking of purchasing a Steadicam Pilot with V-lock mount. But I would like to know what my battery options are. Surely I could go ahead and buy an IDX set for a few hundred euro's, but since I only need to use these batteries for the Pilot, maybe there's a cheaper (but good enough) solution next to the AA battery option.

I was thinking about the Swit kit. You get two S-5056 56W/h NiMH v-mount (I believe this should be V-Lock) batteries and a SC-302S dual charger for about 350 euro.

Anyone tried this Swit system? I want to know if it's any good.

Short answer: I believe your best options are:
1) Pilot-AA plus 2 spare battery holders, 30 NiMH AA batteries, and 2 one-hour 8-slot chargers.
2) Pilot-VLB (includes 2 IDX batts & charger).

If you use the Sony EX3, then option #2 above becomes necessary, otherwise I prefer option #1 for lower cost, faster charge times, and better compatibility with my other equipment.

Long answer: This thread talks about a lot of battery options, including the Swit:
http://www.dvinfo.net/conf/stabilizers-steadicam-etc/141422-steadicam-pilot-aa-battery-mod.html

I've got 4 x Swit S-8082S, with dual charger. No worries so far, had them for six months. 88W and 1.7lb each, so maybe a bit large for the Pilot.