are you talking about something like a sony1024? yes. you can get an S-output and composite out into your media 100 and adjust your image (usually powerpoint) to fit inside broadcast safe areas. I only use this method if i need to record live builds and animations from powerpoint. if it is just static slides, you can export them out of powerpoint , resize them in photoshop and get pretty good looking results there. Sometimes really saturated colors do not translate very well, but you can usually get a sharper picture if you keep it all digital.
I've also use an old Panasonic MX50 panasonic switcher to act as a frame syncronizer for digitizing rough VHS footage. There is a very slight audio delay because of the video processing, but it is very minimal. I've also used an old JVC frame syncronizer to convert composite, S, and component signals in and out. that worked out pretty well too until the unit started displaying nasty diagonal lines.
I just picked up Apple's iWorks software. It can create a QT movie in any codec from a PowerPoint file. The cool part is it will create it with all the transitions intact! Great way to easily import PP shows in NLE. And it can resize too. Although it resizes everything similar to using a scan-converter but better PQ.