SF wargaming rules for my Mechwarrior figures

I’ve been tinkering with some thoughts on new rules sets for use with my Mechwarrior figures. Take a look at the extended if you’re interested, and feel free to comment.

Since deciding that I was no longer interested in playing with the Mechwarrior rules, I’ve been trying to settle on a rules set that I’d like to use them with. Initially, I chose to try and keep ground scale and miniature scale the same (see this page for an explanation of terms). This would make any physically representable battle a very close-range affair, as Mechwarrior figures are N scale.
This turned out to be a little fiddly and unsatisfying and I liked some aspects of the new Axis & Allies miniatures game, so I put some thought into adapting those rules to the task. This would convert the game from pure minis to using a hex map. However, there are two reasons I’m not so hot on this idea anymore. First, you need very large hexes to accomodate the miniatures (‘mechs have 2″ diameter bases) which means maps have to be large, and second, AAM involves rolling lots of dice (up to 18) for each attack. Though the system has a kind of elegance, that still means rolling tons of dice.
Now, I’m considering going to a miniatures game with unlinked miniature and ground scales, with the figure bases representing a zone of control for the element in question. With that in mind, I semi-arbitrarily decided on a ground scale of 1″ = 100 meters. Here are some real-world values to put into that scale:
TOW missile: 3,750 meters = 37.5″
120mm smoothbore tank cannon: 5,000 meters = 50″
155mm howizter: 30km = 300″ (25’)
Artillery rockets: up to 300km = 3,000″ (basically, offboard artillery)
25mm chain gun: 2,000 meters = 20″
Infantry carbine engagement range: 100 meters = 1″
Abrams cross-country speed: 30mph (9″ in one minute)
Abrams road top speed: 41mph (14″ in one minute)
Walking infantry: ~4mph (1″ in one minute)
With all this in mind, I might go for one-minute turns with the 1″ = 100 meters ground scale. I like the outcome. Other things I’m considering:
Infantry can choose to double move and not attack or move and attack.
Vehicles can fire on the move.
Vehicles have slow and fast speeds. A vehicle that is not moving must start at slow, then move to fast. There may be other difficulties with being at fast speed (for example, not close assaulting well).
Ranged attacks have two ranges, short and long.
Fire can be ineffective, partially effective, or fully effective. One possible way to handle this would be to roll two dice for each attack, with one success indicating a partially effective attack, and two a fully effective attack (this does create a particular probability curve that I haven’t yet decided if I like). The effectiveness of the attack determines its strength against the defending unit’s armor.
Some asking around yielded a suggested maximum dispersion of a platoon of 100 meters or so — at the scale I’m working with, this means that infantry unit coherency should simply be “infantry bases are touching” (Mechwarrior infantry bases are 3/4″ diameter or so).
Terrain may impose speed limits in addition to, or rather than, increased movement costs.