I want to appologise for the rudenss of what I said above.. I would be overjoyed if we could do it in SL without asking for client extentions, but I don't think we're at that point yet.
Ok I'm not EXACTLY sure what Joe Debs whant from this proposal, but I'll tell you what I think we need. That cant really be done in the current system at all.
NUmber one is improved group permissions. The ability to set user rights across the group's properties, objects, scripts and any other settings related to the group.
Number two is group inventory space. Right now all objects owned by groups are in world or in object inventory. I'd like to see a group inventory similar to the Library inventory, but with full control over member access and rights similar to the unix filesystem permissions as mentioned above. This I think would improve collaborative building, making it simple to keep track of objects, textures, scripts etc.. that are used by the group. They would be rezed in world as a group object and be accessable only to those with permissions to edit them.
Ok, for the other stuff...
Tacked on was group L$... This would make things simpler for accessing group funds instantly.. with real time tracking just like is available to residents.
Other more farflung ideas were book keeping and employee salarys but that's something that would best be adressed by an enforcable contract. I have 2 votes in the contracts proposal.

Alt accounts wouldnt be such a hastle if you were not restricted by script interface...
I suppose the next best option is a secure website which tracks your alt account and transfers money automagicly when you click the button.
The best option I think over all would include a user programmable user interface such as the one suggested by Cienna Rand. That would require support from Linden Lab, but would open up the possibility of a whole range of new easy to manage scripted systems.
Ideally when you register for Second Life in the future you are not singing up as "Joe Blow" but as a non-descriptive entity, which you may give form or identity however you please.
An extention of this would be the merging of accounts after a wedding or something like that....
I admit my ideas are sometimes little more than metephore, but I'm not a software developer ;P Tha'ts your job .. If you cant understand what I mean I can always try to say it another way..