Is it possible to use LightDM in 11.04?
There is a PPA for natty though this article warns that it's a development release, may cause problems, etc. so there is some risk at this point. If you go for it I'd like to hear your results.
In my opinion its not advisable to try out LightDM. I have tried it and I have run into issues with my GUI. I had to go into recovery mode and uninstall it. If you want to try it out, use virtualbox .