48-port switches with inline power in a stackable format are not available at this time. I have no idea whether there are any plans for such a switch.
48-port switch modules with inline power are available for the Catalyst 4000 and 6000 series chassis switches. I have found that if you have Gigabit Ethernet ports available in a chassis switch, it is usually less expensive to install the stackable inline power switches and uplink them via Gigabit versus using the inline power modules. But the modules are a more elegant solution.
There is a Cisco product called the Inline Power Patch Panel (WS-PWR-PANEL), which looks like a 96-port stackable switch. It lets you take up to 48 10/100 Ethernet connections from regular switches, and add inline power to those cables.
There are also third-party companies that supply in-line power solutions which are Cisco-compatible. Red Hawk is one I am familiar with, that lets you go from as small as a 1-port chassis to a 20-port modular chassis. This can be more cost-effective if you don't need many inline power feeds from a particular switch. These solutions can also be effective if you need to supply inline power to other vendors' equipment. Red Hawk's modular products let you mix and match the inline power supplied (Cisco, IEEE 802.3af, or 24-Volt), on a per-cable-run basis, so you can use non-Cisco WAPs and Ethernet phones with Cisco switches. Here's a link to their site:
http://www.red-hawk.com/products/copper/network/bl8000.htm
This lets you put a centrally-located UPS on the switch and in-line power source, rather than resorting to transformers and power packs with individual UPSs near each device. Keeps the clutter at the end-user's location to a minimum.
Hope this helps too.
