Hi at the present moment,
the VM team are working on The multi vendor option where you can add sepearte vendors to the one shop. the idea being that you could have one shop for a number of persons.
* I see quite a few people looking at your question so I though I'd just add a thought.
* If you had one person doing the the shop - they control stock, products uploading etc.
* * Your sales reps really they don't need any access as they are promoting / selling your products -
* They simply email - images and costs to the store controller who puts up the products -
* To sell they then find a customer - they the sales rep puts the product in the shopping cart while sitting with the customer - the customer puts in their own details but you have added an extra field - the extra field could simply be a code of the seller or could be their email, name etc.
the customer will get the product - you will be able to tell which sales rep sold the product and no one wil be able to access the site.
* to make it really basic - all reps have a given number - the customer could go home - purchase the product themselves and type the reps code in the extra filed themselves.
* at the end of the month - as a finance option ( software like MYOB - that interacts with VM could easily sort commissions based upon one filed - which would be the sellers code)
* Or siimpy download the Data base and sort in Excel - spreadsheet.
* the only limited option to give a seller to login and have access is to given them a public and administrator password - ( they need to be admin to get access to VM) - but that also gives them accesss to maybe too much access in Joomla and also they can see "orders and sales" - so that is not really an option for you.
* there is some software that I have seen in the Joomla extensions that does allow an upload and storage of images to the Website "instead of email" - look in extensions 'communication' free - here that click add an email or contact sales rep name and then attach, picture, cost etc. and it uploads to the website- the store will get an email notification.
In reality VM - multi - vendor option is not far away from trials - but limited access to some modules is being looked at.
* I am not part of the team that is developing the software in that area.
* MYOB - example
http://www.m2j.com.au/