Using standard 1E rules, an elf could become a Ftr7/MU11, roughly the equivalent of a Ftr2/Wiz11 in 3E.
Using standard 2E rules, an elf could become a Ftr 12/Wiz 15, roughly the equivalent of a Ftr 4/Wizard 15 in 3E.
I very much enjoy Tome and Blood - a quick reminder of the "multi-class" combinations within it:
Arcane Trickster: Wizard/Rogue multiclass; requires Rog4/Wiz5 to become, only gets 4 skill points per level, gains Wiz spells every level, gains sneak attack as normal, plus some other minor abilities.
Bladesinger: elvish Fighter/Wizard multiclass: minor dedicated spell-list, errataed version available as a free download from Wizards (See the Tome & Blood web expansion).
Spellsword: Fighter/Wizard multiclass: can cast spells in progressively heavier armour, +1 spell level per two levels, Cleric BAB, plus some other fun abilities. (probably requires a Ftr1/Wiz6, a Ftr2/Wiz4, or a Ftr3/Wiz3 to become).
Cheers!