"Open with" command

Frequently when working in the main SourceTree window for a repository, I'll be working in the working copy and need to open a file (e.g. to resolve a merge conflict).

I will right-click and bring up the contextual menu to "Open".

This is alright, but sometimes I need to open it in a specific application. For example, I need to edit a .html file. If I merely "open" it, it will open in Safari, which is not what I want to resolve that conflict. Instead, having an option to "Open With" (and presenting a submenu of apps that could open files of that type... just like the Finder does), would be greatly helpful. That way I could be sure to open the conflicted .html file in TextWrangler or TextMate or whatever may be most appropriate.

It would also be useful if this would be sure to open the file. For example, when an Xcode project file's .pbxproj file is conflicted in a merge, a simple "open" fails to work because the file is technically within a package and thus cannot just be opened by the Finder. If Open With (and/or Open) could open the actual file, that'd be great... but I know that's a bit harder to do in a generalized manner.

Anyways, Open With would strive to replicate how the Finder works in this regard, if at all possible. Being able to dynamically build a list of apps on the user's system and present them. Also an option to select "Other..." if needed. If it's not possible or is too costly to generate that list of apps, having a SourceTree preferences panel would be cool to help handle files of particular types... e.g. for files with this extension, use this app to open it. Prepopulate with a lot of known and common extensions, allow ease of editing those mappings, and if something is selected via "Other..", automatically pick up that new mapping.