^I'm curious, though... what if Gordon-Levitt's character in the film had been named Terry McGinnis?
On the other hand, the hardcore fan in me knows that the Wayne money is old money. Bruce inherited Wayne Enterprises, yet his father was a doctor who couldn't really create a multi-billion dollar company, so even he must have had inherited. You could have Bruce be adopted, but then he'd be orphaned twice, which seems kinda silly.
The first African-American to own a billion-dollar company was Reginald Lewis, who acquired Beatrice International Foods in 1987 and was listed by Forbes as one of the 400 richest Americans in 1992, a year before he died. If we assume a Batman who was born in the early 1980s, making him a bit over 30 now, his parents certainly could've been worth hundreds of millions by the time of their murder c. 1990. They wouldn't have inherited, but he could have.
And who says Thomas couldn't have created a corporation? Maybe he started out as a doctor, but invented some medical advance that made him rich, or bought a pharmaceutical manufacturer or something.
Sure, traditionally the Waynes are portrayed as old money, but adaptations let you reinvent things.