Is it possible to have EPiServer 4.61 and EPiServer 7 installed on the same development machine?
It's possible to run EPiServer 7 and EPiServer CMS 6 on the same machine, but it does require some small manual steps: http://sdkbeta.episerver.com/SDK-html-Container/?path=/SdkDocuments/CMS/7/Knowledge%20Base/Developer%20Guide/Upgrading/Running%20CMS%206%20R2%20and%20CMS%207%20Side-by-Side.htm&vppRoot=/SdkDocuments//CMS/7/Knowledge%20Base/Developer%20Guide/
I guess that the same would apply all the way back to CMS 4.61, but I'm not sure that has been tested.
Alternatively, can I develop a EPiServer 4.61 based site (in Visual Studio) on a development machine without having EPiServer 4.61 installed?
I'm not sure I completly follow you, what do you mean by having it installed? Are we talking about the visual studio integration, or having a site installed from the EPiServer Manager.
Anyway, to be able to develop a 4.61 site in visual studio what you only really need is references to the EPiServer 4.61 assemblies. And of course a local copy of your site that you deploy your code to.
Having EPiServer 4.61 installed as in having that version of EPiServer CMS listed in "Programs and Features" in the Control Panel.
The EPiServer site and database already exist. I only need to do maintenance work on the development machine, i.e. building and running the site in Visual Studio. I do not need to create any new EPiServer 4.61 site.
Yes, that shouldn't be any problem. Might require some manual steps, but should work.
Per Gunsarfs, your link about possibility to run EPiServer 7 and EPiServer CMS 6 on the same machine, are brokwn :-(
Try this, http://world.episerver.com/Documentation/Items/Upgrading/EPiServer-CMS/7/7/Pages/Upgrading/#SideBySide.