The original bases I used are from dark age games but I did some cutting so everything would fit on a single base.
The standard base that the xv-9 comes with is a 65mm dreadnought base.
After I get the castings done for personal use I'm going to produce a bunch of these until the mold wear out. May toss a few up on ebay or batertown etc.
As far as bases I love the dark age games stuff, I also carry them through my store and I'll have them up on my website when I relauch it in Jan. The DAG website is kinda crappy and I have problems navigating it, you can find pics of all their various bases in the coolminiornot store or on ebay or warstore etc. The only downside is their stuff is only available in 30,40,50mm sizes and there's very few quality 60mm bases so I hacked together this base from a 50mm DAG base and a pair of their 30 mm ones that I trimmed to fit.
The DAG stuff is designed to fit into the recessed top of rounded shoulder bases which they also sell and are identical to the privateerpress bases. (which I'll also be carrying) Custom built bases are usually quite cheap, but premade resin bases also save time. You can also glue them down on standard GW bases but they usually need a bit of filing around the edges.
I used the 50mm base on my commander model, it's kinda hard to see so I'll post some clearer pics up soon. For the regular suits I'll be using 40 mm bases, I just like putting HQ models on larger more scenic bases.
I'm looking at producing my own bases once I get caught up on my current projects. The space hulk tiles are next and then hopefully bases.
This suit is mounted on a 50mm DAG base so it's slightly larger than the normal terminator base.
Edit:
Size comparisons the lower set of bases is privateer press or DAG generic round shoulder base
Differance in the edging GW vs Privateer
GW Dreadnought vs 50mm base
Here's a couple pics of the various DAG bases.
Generally retail prices at:
30mm (3) $5.99
40mm (2) $4.99
50mm (1) $2.99