A look inside the Expander's box (pictures courtesy of the FCC filings) show a design that, at least from a component point of view, is very similar to Linksys' cost-redesigned WAP54G v2 access point. Both are based on the Broadcom BCM4712 "System-on-a-chip" processor and AirForce chipset rounded out by RAM and Flash.
Figure 2: Top of WRE54G board
Figure 3: Bottom of WRE54G board
As I pointed out previously, however, an important difference between the WRE54G and its other Linksys cousins is that it lacks the Ethernet port necessary for wired setup and wired-LAN bridging.