I'm going to take a different tack and suggest that
TW might not be exactly what you are looking for
I've played
TW a few times and it might be what you want, but it's a drastically different game.
Am I right in thinking that I can quite literally use [i]anything?[/i]
Yes.
More specifically, can I model a hefty marine carrying an Assualt Cannon or a more modern M16?
Kind of, but not the way you are thinking. Weapons in Tomorrow's war are much more abstracted than in
40k. The empahais is on Troop quality rather than Troop equipment. An m16 and a Bolter are probably going to be statted about the same.
Or prehaps a scout with a jump pack carring a power axe?
Jump pack yes, though a Power axe is probably just going to be a modifier to your close combat. There is not going to be any functional difference between chainsword, power axe, power sword, power fist, etc.
Are the rules really as accomidating as I'm hoping?
Yes and No. They are less difficult than
40k, but the book is laid out a bit odd in places and it can be hard to find certain rules. Not moreso than
40k I think.
How many weapons are in the book or should I expect to have to sit down and work out most of the stats myself?
All weapons you'd need are provided, but as I said, it's not a long list. It's a matter of a firepower stat and a few special rules.
TW is a game that is not going to give a game that is at all similar to
40k rules.
-The activation mechanic and reaction mechanics are completely different from
40k
-Close combat is near suicidal for most troops. Ranged combat, suppressive fire and fire lanes are the way to victory.
-The quality of troops is the biggest differentiator between units rather than weapons or other stats.
-
TW does not have a points system (there's one online, but its not intended to be super accurate). It's not a game for pickup-play, rather it's designed for scenario play.
The one thing that
TW would do really well for the
40k universe is simulate a "realistic" style of play, where Space marines are as deadly as they are in
40k fluff. In
TW A group of elite soldiers in Power armor can really wipe the floors with hordes of low-quality troops.
For games that might be more up your alley, check out:
-"No Limits"
http://www.wargamesunlimited.net/nolimits/index.html
It's basically the freeware version of the Game VOR. It will give an experience more similar to
40k, with a bit more realistic mechanics while still keeping the sci-fantasy feel and incorporating a more effective
CC phase. The game has lots of provided force lists and a very nice unit creation mechanic so you can stat up anything.
-The new version of Warpath. (the original is fun, but very abstracted and suited for mass battles only)
Known as Warpath 2.0 or Warpath Skirmish, it's got many similarities to
40k, but is alot faster moving. No unit creation mechanic yet, but lots of sample units are provided.
- "WarEngine". The old website is a virus bomb, and the new site with in-progress-new-edition is near useless, but it's worth joining the yahoo group to get access to Warengine 2.1.
http://games.groups.yahoo.com/group/WarEngine/
It's basically the same game as "Shockforce" which is definitely sci-fantasy with some really fun dice mechanics, a great unit builder and good game flow. The one drawback is that it doesn't handle Tanks and large vehicles very well, though you can certainly house-rule for them.
Sum up.
TW is a good game, but I caution folks coming from
40k that it is not going really going to be at all like
40k. If you want a "Hard Sci-Fi" experience, then
TW is your thing, but based on your questions, I think you will find that
TW is not what you're looking for. I own it and play from time to time, but when I want a game for using my
40k figures, it's not
TW I turn to. Warpath and WarEngine are my favorites, though No Limits is definitely worth looking into.
All the best on your rules quest.