howdy!
top stuff to see people finding Bloomilk, and enjoying SWMinis

also, apologies for the impending information overload - you ask excellent questions though

VSets are optional cards that the Bloomilk/SWMinis community has continued to make beyond the end of the WotC game - which ended circa 2010. TheHutts outlines elsewhere how VSets compare to other cards, and the design process is interesting to find out more about;
basically, theres a thread where people request things which have not yet had a mini made, or would like a different variant of,
and then the committee gets to work designing and playtesting.
VSets are balanced to the later WotC sets... so, there is a degree of 'power-creep'... folks who prefer a particular 'meta' game tend not to adopt them,
and even now in 2015, some folks at tournaments etc have never heard of nor googled SWMinis VSets hehe
this has led to different formats of the game emerging alongside staples such as tile wars, dynamic duos, 200, 250, 300, 500+mega games etc
for example: VSet Epic cards are designed to be 'penultimate' versions of the character, and to be used in the larger points formats.
While they make for highstakes dynamic duos... using an Epic VSet card against a squad with no epic vset card or counter to that card... can be frustrating

turning to VSet cards themselves;
there's lots of options;
you can print them yourself if you have a lazer A3 printer and 180-190GSM non-gloss cardstock to hand (simply use clear-coate spray sealer as it won't react with the card/ink and will make it 'stain resistant' heheh)
You get about 20 odd cards per sheet of cardstock that way
you can take the files from online to a local print-shop, say officewerks or an independent etc, and they'll print them out for you. If you're feeling experiment-y, you can try making decoupage or clear cards, etched-embossed metal cards, etc... This can be difficult to specify, and you'll often need to fill a whole A3 sheet etc... yet, luckily the files are print-ready CBYMK'd for printing, so that is awesome and an option.
the card thickness should be 1.75-2.3mm (there was a lot of variation in the cardstock used in WotC statcards)
these places often also offer a cutting service too - so they make a great one-stop shop, especially if you only want 15 copies of the 1 card itself...
lastly, you can barter with the folks who make the official card sets, when they make their reprint drives or cloudfunding campaigns -
this can be expensive, yet, the quality is second to few

Tech-specs on the cards:
Dim.: |63mm W| x |88mm L| x |1.75~2.3mm D| {avg.}
factor in bleed space and the skill of whoever is cutting the cards from the sheet when leaving gutters

80-90gsm is regular paper - 2 of these stuck together, or 1 + laminate = the thickness you're looking for.
180gsm is a comparable thickness to the cardstock the actual cards are made from.
on the other end, 220gsm is way too thick, and inflexible, and wont fit into ultrapro card protector sleeves.
however, may be excellent for making "Staggered Activation" statcards
Hopefully this is more info than you'll need to use heheh,
it's a topic of research that's really interesting about the customs --- the level of detail some folks go to,
making the custom cards, a custom miniature even a custom booster-package...
and, hopefully we'll see you on Bloomilk in future (particularly the custom minis fora)!