[sorry, same note, right tor-relays address this time :-]
I got to a point where I want to make an active contribution to the Tor cause starting with running some nodes of my own, but I'm having difficulties on finding hosting companies (vps/dedicated) that allow running Tor services.
I know that you've been resuming your servers in the Netherlands Would like to hear what's your experience with that.
There is not much advice I can give you. I do not want to recommend any of our ISPs, not because we're not happy with them (to the contrary), but because it makes no sense to put more and more Tor exits into few places. My strategy always is to find appropriate offers (cheap high bandwidth) and then contact the ISP. This has evolved into a pretty standardized two-step approach: First, I ask if they were okay "with Tor" and reassigning IP space, and telling them that we're security researchers and that we have worked with many ISPs successfully in the past. Because the reassignment is somewhat of a special case, this usually helps in reaching someone higher up in the support chain who can make such decisions. Once they get back to me, I explain Tor a little more and only then tell them about the caveats, but reassure them that we have a volunteer team handling abuse around the clock etc.
Depending on what you're able and willing to spend, a good approach would be to look for data centers, and ask there for potential partners. I wrote a small script that puts the GeoIP location of Tor nodes on a map, which is somewhat helpful in finding "empty spots". A good idea would be a script that extracts ASNs, sums up "their" Tor bandwidth, and then not go with those that already have a high bandwidth exit, but maybe some other AS in the same datacenters?
Yes! Far better to look for new diverse holes and fill them than to essentially duplicate existing nodes.
Bringing in tor-relays on this, as this topic comes up there once in a while too.
I'll add that AS path info is available from route views looking glasses. Think of it like traceroute, but for BGP. It's quite handy.
A node map showing current GEO, AS, and provider would be a cool idea. Lots of cities have datacenters and moms/pops of some sort. People could then find a gap near them, then poke around the phonebook, webhostingtalk, datacentertalk, [NA]NOG's, etc to find a diverse fill.