Hi guys havn't posted for awhile but just thought I'd put in my GWS 2cents
worth.

Of all the 40k armies the Imperial Guard figures would be the quickest and
easiest to place into Slammer. Simply ignore the Gamesworkshop stats and work of
what the figures have. The organisation and tactics are such a blatant ripoff of
WW2 and coldwar Soviets you can pretty much follow modern standard human type
army norms.

If you start getting into 'exotics' then look at what the intended effect is.

Space Marines I would class as expensive Super Soldiers, more Androids then
humans fearless, resistant to damage heavily armoured and extremely well
trained.

Tau, probably the closest to the idea of what a 22nd centary army here on earth
might be like.

Tyranids, nasty, smart, bugs with guns.

Orcs, fanatical mobs/collapsed civilisation/escaped Gene experiments that breed?

Elves might be a decaying empire where warfare has evolved/devolved/stagnated to
a ritualised Clan warrior style, brilliant and advanced but lacking innovation
and resistant to new ideas.

All these are just some ideas I've used myself and could be mix and match for
any of the armies/figures.

Same thing working with the weapons, what it's called dosent overly matter, just
look at its intended effect. A Bolter is just another name for a larger caliber
Pulse rifle etc. Pretty much everything can be placed or shoe horned into what
Slammer has now in the rules similer to my WW2 weapon sheet I madeup.

However almost all 40k weapons as shown in game as opposed to in the
books/stories are extremly short ranged and inaccurate.