http://www.dakkadakka.com/dakkaforum/posts/list/8.page JForum - http://www.jforum.net https://www.greenstuffworld.com/en/hobby-accessories/1624-hollow-plastic-bases-black.html but they have rather limited offering of sizes. They don't make round bases larger than 32mm. After some searching on Google, I found that there should also be hollow bases from Beveled Edge but those don't seem to be widely available in UK and they are quite expensive - almost 10 GBP for a single 105x70 seems to be quite lot considering that it is not even a scenic base.

I don't own 3d printer myself so can't print them myself.]]> http://www.dakkadakka.com/dakkaforum/posts/preList/800766/11213706.page http://www.dakkadakka.com/dakkaforum/posts/preList/800766/11213706.page GMT
This is what I had to do when I had the same need for hollow bases and saw the same struggle with getting hold of them in the UK.]]> http://www.dakkadakka.com/dakkaforum/posts/preList/800766/11213940.page http://www.dakkadakka.com/dakkaforum/posts/preList/800766/11213940.page GMT PP's do.]]> http://www.dakkadakka.com/dakkaforum/posts/preList/800766/11214045.page http://www.dakkadakka.com/dakkaforum/posts/preList/800766/11214045.page GMT http://dragonforge.com/

they have round lip(similar to what you're looking for) with various size and patterns. ]]> http://www.dakkadakka.com/dakkaforum/posts/preList/800766/11214068.page http://www.dakkadakka.com/dakkaforum/posts/preList/800766/11214068.page GMT