No.. not a typo. According to PC World, Prodisc will be unveiling 4.9GB discs at Computex.
http://www.pcworld.com/news/article/0,aid,120975,00.asp
The catch is that its supported by only 15 drives:
Behaviour Tech Computer's (BTC) DRW1108IM
BenQ's DW1620
LG Electronics' GSA-4082B and GSA4120B
Lite-On Technology's SOHW-1613S
NEC's ND-3500A
Optorite's DD0401
Pioneer's DVR-107D and DVR108
Plextor's PX-708A and PX-712A
Ricoh's MP-5308D
Samsung Electronics' SH-W08A
Teac's DV-W58D
Toshiba's SD-R5272