They look good old one and are probably the cheapest options from what I can see. Better than cutting and grinding your own for sure. When doing my own MDF bases I tend to make them a little smaller so the plastic bases glued onto the minis slightly overhang the MDF base. I've also seen balsa wood used which is a heck of a lot easier and safer to work with (particularly if using a blade to cut the bases rather than a saw, as blade-cutting is a lot more dangerous).
Regarding commercially-available bases during the KoW 2 kickstarter Mantic also linked us to some other sites that might be of interest to those of us into cool multi-bases. Here are some of those links for anyone interested:
MDF Movement Trays
http://war-bases.co.uk/index.php?route= ... uct_id=646
click in the 'Movement Trays' icon and you will see KoW trays towards the bottom right. They can accommodate round and square bases (so look good for placing any round based models, e.g. LoTR/Hobbit minis in movement trays). I have not ordered any so don't know how good they are.
(Edit) You can order MDF trays direct from Mantic too (these are also Warbases trays I think). Below is the link (it is under the 'New' tab).
http://www.manticgames.com/mantic-shop/ ... f-war.html
Just scroll down a bit after you click on the link and you will see them.
These appear to be more costly than the cut trays linked by oldone but may have their uses.
DIY textured scenic bases and multi-bases
http://www.wargamesbakery.co.uk/wargame ... asius.html
https://www.kickstarter.com/projects/20 ... ts/1015348
Again I have not used these so not sure how good they are.
I am sure there will be others out there as well. So if anyone knows additional potential tray sources (particularly local sources) for cheap but good movement trays please link us in.