Right off the bat you can get similar posing potential and more accurate proportions for cheaper (albeit a little smaller - I think it is 1/8 as opposed to 1/6) :
Now I think there are a few reasons behind the odd proportions of the Medicom and HotToys bases. I think one of them is the design legacy of old school 12 inch actions figures in general, with the requirement to make swappable heads compatible. But another thing to consider is that these figures are supposed to be "dressed up" with toy-scaled fabric outfits, which all have a very thick feel to them, requiring a very slim body base underneath or easy manipulation. Weird stuff.
Personally I think that if you want to use any of these for pose and proportion reference, the cheap toys are just as good. But of course opinions may vary...
Are there better more expensive ones than the one linked above?
This one's not even for sale. It's used by Japanese toy companies just for marketing purposes (trade shows). You can customized power ranger toys (from ebay) based on this articulation (matte out colored paints, kitbash parts to simplify, etc.)
I did a bunch of research on this a while back when I was looking into the possibility of making my own 3d printed figures.
Depending on exactly what you're planning to do with these things, the "Takara Microman Material Force" might be a pretty good option. Takara make loads of articulated figures, but the "Material Force" figures are blank ones with nice, relatively realistic proportions (idealised, but not the nasty anime proportions that a lot of these things have) and good articulation. They come with sets of hands you can swap out.
I think the only viabe place to get them is on EBay. They're not exactly cheap. Possibly you might be able to get some kind of other Takara Microman model built on the same base, like a superhero or whatever else, which you might potentially be able to find cheaper.
Replies
[ame="http://www.amazon.com/Deluxe-UFC-Figures-Tito-Ortiz/dp/B003KN2688/ref=sr_1_4?s=toys-and-games&ie=UTF8&qid=1387596833&sr=1-4&keywords=ufc+action+figure"]Amazon.com : Deluxe UFC Figures #6 Tito Ortiz : Action Figures : Toys & Games[/ame]
You can also go more high-end and go with HotToys, some of which feature a natural flexible skin mterial, and better proportions than the Medicom (but still a giraffe neck)
[ame="http://www.amazon.com/Hot-Toys-TrueType-Generation-Caucasian/dp/B005C91C6U/ref=sr_1_9?s=toys-and-games&ie=UTF8&qid=1387596934&sr=1-9&keywords=hot+toys+male"]Amazon.com: Hot Toys TrueType - 1/6 Scale Action Figure Body: New Generation - Caucasian Male (Muscular Body Version): Toys & Games[/ame]
Now I think there are a few reasons behind the odd proportions of the Medicom and HotToys bases. I think one of them is the design legacy of old school 12 inch actions figures in general, with the requirement to make swappable heads compatible. But another thing to consider is that these figures are supposed to be "dressed up" with toy-scaled fabric outfits, which all have a very thick feel to them, requiring a very slim body base underneath or easy manipulation. Weird stuff.
Personally I think that if you want to use any of these for pose and proportion reference, the cheap toys are just as good. But of course opinions may vary...
This one's not even for sale. It's used by Japanese toy companies just for marketing purposes (trade shows). You can customized power ranger toys (from ebay) based on this articulation (matte out colored paints, kitbash parts to simplify, etc.)
keyword: Figuarts
Depending on exactly what you're planning to do with these things, the "Takara Microman Material Force" might be a pretty good option. Takara make loads of articulated figures, but the "Material Force" figures are blank ones with nice, relatively realistic proportions (idealised, but not the nasty anime proportions that a lot of these things have) and good articulation. They come with sets of hands you can swap out.
I think the only viabe place to get them is on EBay. They're not exactly cheap. Possibly you might be able to get some kind of other Takara Microman model built on the same base, like a superhero or whatever else, which you might potentially be able to find cheaper.