FCC wants to open 255 MHz more bandwidth in the 5 GHz range [PDF]: This proposed rulemaking is in line with the Boxer/Allen (Senate) and Honda (House) bills to expand unlicensed bandwidth. It could breathe new life in 802.11a, by allowing potentially 20 channels total instead of the current 12, allowing extremely dense installations.
The 3 channel limit is one thing holding back 802.11a popularity, especially for indoor installations. Two other frustrating things about the technology are a) none of the manufacturers offers replaceable antennas (except Proxim on their "dumb" 8571), which severely limits both indoor and outdoor deployment, and b) apparently none of the radio chipmakers are even fabricating high-band (5.8Ghz) capable radios.
WHY??
802.11a has 12 channels, although some devices only support the lower 8 channels, as the upper 4 channels are reserved for outdoor point-to-point applications.
Antennas must be certified for use with specific devices: you can't have a legal generic antenna. Some manufacturers do offer other antennas. You can purchase non-certified antennas, but using them is illegal. However, there hasn't been any enforcement action on this (yet).
Oops, I was thinking of b's 3 channel limit. Anyway, what's puzzling to me is that the same antenna certification rules you mention apply in the 2.4GHz spectrum, where add-on antennas are plentiful. Also, 5GHz products with replaceable antennas are readily available. It's only in the 802.11a space that manufacturers are showing such restraint. To me, this is the biggest reason the technology isn't taking off like it could.
If the 802.11a Indoor equipment (aka cheaper APs) are capable of external antennas, then the UNII spectrum will be heading down the same path as the 2.4Ghz as there will be no spectrum left eventually b'coz everyone will be putting up the largest gain Omni they can get hold of ..