I would agree with your chosen races except maybe the Markab. Obviously, the only way you could have the Markab is if you base your campaign before late 2259 or you "bend the rule" and assume that a handful of Markab survived.
You could add a race like the Abbai or the Hyach, but the Pak'ma'ra and Gaim are already obscure enough. They may always be around, but we don't know much about them. At least with the Drazi, we've seen their homeworld, we know a little of their culture, and we know a little bit about their biology.
You could almost get by on just the four main non-First-One races plus the Drazi. Also, how about the Brakiri? Don't know too much about them either, but they'd probably be easier to take dramatic license with than the Pak'ma'ra or Gaim. I mean that Day of the Dead thing is pretty mysterious.
To expand on the class concept, here are a few ideas:
<UL TYPE=SQUARE>
<LI> Administrator/Governor: for Human Senators, Centaurum members, Kha'Ri members, Grey Council members, Drazi Green/Purple leaders; these examples are probably best for the elite version of this class; could be the class that ombudsmen (station court judges) fall into
<LI> Archeologist/Scientist: for IPX members like Anna Sheridan & Max Eilerson; could be called IPX class if you want it specific, or you could keep it general and call it Scientist class
<LI> Aristocrat: this would be mostly for Centauri; would be the class for members of the noble Houses and the royal court
<LI> Business Mogul: like William Edgars and the Garibaldi of the future; could be an elite version of the Merchant class or could even be included as a subcategory of Aristocrat; this could be a favored class of the Brakiri, as I read somewhere they're very businesslike
<LI> Cleric/Clergy: a major aspect in the B5 universe portrayed by the entire Minbari religious caste, Brother Theo's monks, Reverend Dexter, 5th Season G'Kar, etc.
<LI> Colonist: this could be a "catch-all" for people who farm, build, terraform, etc. on a habitable alien world
<LI> Diplomat: for Ambassadors, Attache's, business negotiators, etc.; this is a crucial class in the B5 universe, but members are often multi-class (G'Kar and Delenn were both diplomats and "administrators", Londo was a diplomat and an aristocrat, and Sheridan & Sinclair were both Soldiers doubling as council representatives)
<LI> Entertainer: like the Centauri jester and Cailyn the singer Franklin met in downbelow
<LI> Investigator/Police/Security: like station security and forensics; could be the class that ombudsmen would fall into
<LI> Medic/Surgeon/Healer: doctors, nurses, and clinic facilitators such as Dr. Laura Rosen (Ep. 121 The Quality of Mercy)
<LI> Merchant: bartenders, Zocolo kiosk owners, black market sellers, gambling facilitators, those struggling in downbelow, etc.
<LI> Pilot: like Lt. Keffer; granted, there are lots of B5 people trained in piloting, but these would be specialists like Keffer who weren't good for anything else
<LI> Ranger: lump this into Soldier if you don't make Ranger it's own separate class
<LI> Reporter/Journalist: another important aspect of the B5 universe; would include ISN reporters, alien reporters, and those working behind the scenes to cause propoganda; could include writers like G'Kar if Writer isn't good enough to be it's own separate class
<LI> Rogue/Thief: like Dureena Nafeel; on B5, thieves were all over the place; guild members could be considered elite
<LI> Soldier: like Ta'Lon, Minbari warrior caste members, Earth Force members, marines, etc.; could include Rangers if Rangers aren't their own separate class; could also include security personnel if you don't include Investigator/Police/Security as a separate class
<LI> Technomage: like Galen, Elric, Alwyn, etc.; self-explanatory
<LI> Telepath: like Talia, Lyta, Bester, Byron, etc.; if you just make telepathy a skill instead of making Telepath a totally separate class, use Psi-Cop as an example of another appropriate class such as Administrator or Investigator/Police/Security; keep in mind that Minbari telepaths are usually--if not always--a part of the religious caste
<LI> Worker/Engineer: for Minbari worker class members and folks like Mack and Bo
<LI> Writer/Philosopher: for folks like G'Kar; this may be best to lump into another class
[/list]
Hope this helps.
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[This message has been edited by Ninja_Squirrel (edited November 18, 2001).]