[LightDestory]

having an available os list is futile and unnecessary work too.

on kvm systems,
you can install almost anything from iso on hdd by a little searching on Google.. i always download the netinstall image on storage after partitioning and go from there.

Please thing about it and read all the conversation before reply.
As I have already stated, this suggestion applies well to OpenVZ VPSes because these VPSes have LIMITED CHOOSE and currently only someone that know about OpenVZ 6 or Virtuozzo 7 (OpenVZ 7) wiki can find the available OS.

Fortunately VPS providers are starting to leave OpenVZ 6 virtualization: some, like VirMach, is switching over KVM, others are upgrading to Virtuozzo 7 (because it is still a very good cheap and overselling solution).

Regarding your suggestion about 'netinstall image'... how can VPS holders without Control Panel do it? Do you know how many VPS that uses KVM virtualization comes without Control Panel? 
I will liste them for you:

• 2x VPS 6
  
• 7x VPS 9 (Soon when VirMach will finish its upgrading)
  
• 1x VPS 17
  
• 2x VPS 18
  

For at total of 12 VPS out of 32 VPSes. Currently you have to ask staff which OS are available to use and then ask again to install it for you. If you know already what OSes are available you can short the communications and increase the efficiency.
As I have already said, this feedback isn't intended to add much work, we are talking about low frequency changing lists: OpenVZ lists are likely freezed, "Custom ISO Mount" is not a service that all can use, for example VirMach doesn't provide on Post4VPS's sponsored VPSes, so KVM list can be see as fixed list that doesn't change so often.