Well I dont know if any ones going to read this but what the hey. a few months ago I went over the Field manules and the new house books (well the ones that are avalible any way) over the rank systems.

This is the ranks currently in use by the house militarys. With a quick note on the level of command that rank is typicly found.

Lyran alliance
Recrute -Training
Private -After training
Private 1c -After 6 months
-------------------
Corporal -fireteam?
Senior Corporal -squad
Sergeant -squad, veh cmder (mechwarrior)
Staff Sergeant -platoon (inf/veh pltn cmder) (5 years exp)
Sergeant Major -platoon/company
Staff Sergeant Major -Battalion
Senior Sergeant Major -Regiment (20 years exp)
--------------------
Warrant officer -tech
Warrant officer 1c -work squad
Senior warrant officer -work ptln
Cheif warrant officer -work company
---------------------
Cadet -Traning
Leutnant -"6 months"
First Leutnant - Platoon commander
Hauptmann - Company Co
Kommandant -Battalion Co
Hauptmann-Kommandant -Senior Btln Co
Leutnant Colonel -Regiment Xo
Colonel -Regiment
Leutnant-General -base commander/ RCT cmder (brigade)
Hauptmann-General -providence comander
Kommandant-General -General Xo
General -Military theater comander
General of the armies

Federated Suns
Recrute
Private
Private First Class -"6 months" promo
Corporal -fireteam
Sergeant -squad /mechwarrior
Sergeant Major -platoon (co)
Command Sergeant Major -battalion / regiment
-----------
Cadets -training
Subaltern - "6 months"
Leftenant -platoon
Captain -company co
Major -battalion
Leftenant Colonel -regiment Xo (senior btln co)
Colonel -regiment co
Leftenant General -bde cmder, planitary milita
Major General -RCT cmder
General -PDZ cmder (RCT cmder)
Marshal -PDZ cmder, department head
Field Marshal - theater cmder
Marshal of the Armies

Free Worlds leage
Recrute
Private
Private first Class  "1 year" promo
Corporal -squad /mechwarrior
Sergeant -platoon (infantry/tank)
Staff Sergeant -company /mechwarrior (typical rank)
Master Sergeant -battalion
Sergeant Major -regiment
----------------------
Lieutenant -platoon
Captain -company
Force commander -battalion
Lieutenant Colonel -senior battalion (infantry or tank regiment)
Colonel -Regiment
General -brigade/division
Marshal -military district
Captain General

Capellan Confenderation
Recrute (private)
Corporal -squad leader
Sergeant -platoon
Master Sergeant -battalion
Command Master Sergent (unafisial) -regiment
------------------------
Lieutenant -squad (platoon infatry & tank) /mechwarrior
Captain -platoon (company infantry & tank)
Major- company (battalion infatry & tank)
Lieutenant Colonel -battalion (regiment infatry & tank -max rank)
Colonel -Mech regiment -base commander
General -"area commander"
Senior General

Draconis Combine
Recrute -traning
Private -after training
Lance Corporal -"6 months"
Corporal -asistent squad/tank leader
Sergeant -squad/tank leader
Master Sergent -platoon /mechwarrior wo/mech
Talon Sergeant -batalion /mechwarrior w/mech
Sergeant Major -regiment
-------------------------
Lieutenant -platoon
Captain -captain
Major -battalion XO (company co)
Lieutenant Colonel -battalion
Colonel -regiment
Brigadier General - generals Aid
General -Prefecture commander
Warlord -military district


All Houses seem to start their mechwarriors at around Sergeant level except the Capellans who start at Lieutenant. (so for the most part most mechwarriors are NCOs and not WOs or Officers)

As for training it seems most mechwarriors take about 3-4 years, though 6 is not unheard of.