The closest thing you're going to find for future performance and equiv performance in dx9 stuff that isn't ati but has all the features would probally be the Gainward FX PowerPack! Ultra/1800XP Golden Sample. I'm personally not familiar with it but it got fairly good reviews and one of the guys at work just got one (does video work) owns one and likes it pretty well. Course you pay out the nose for this thing too... price runs 450-500$ more or a less. There's one on pricewatch for 465ish... here's a quick c&p from gainwards page...
NVIDIA GeForce™ FX 5950 Ultra GPU
Engine clock at 500MHz plus for Golden Sample
256MB ultra fast 2ns DDR
256-bit memory bus
1000 MHz plus date rate for Golden Sample
Multiple Display Support
DB15 for analog VGA
DVI for Digital Flat Panel
DVI-VGA adapter
2x Video-In connectors
2x Video-Out connectors
Both composite and S-video for Video I/O
Optimized for DirectX 9
AGP 8X/4X
I think for the price a high end ati all in wonder might be a better choice but whatever floats yer boat
Shadus