>>I'm not sure any of us should be pontificating on this subject since Gerard has given virtually zero indication of what is required of the app beyond the ability to run disconnected (which, by definition, implies fat client) and that, AFAICS, the client simply wants something that looks like an IPad.

Why tell me? ;-) The proposal is a disconnected iPad app. I've suggested looking at Android as well, trying to provide reasons from the customer's perspective. Others have proposed Silverlight, with the only obvious reason being that they're familiar with it.

>> But aren't there plenty of tablet PCs out there running XP or even Win7 ? How about the HP Slate?

IBM, Dell and Asus recently dropped Windows for their new portable devices while HP recently bought Palm and trademarked the term "PalmPad". Even MS is contributing to the trend by suddenly dumping some of its own mobile efforts and breaking backward compatibility with their latest mobile OS meaning you're starting from a zero existing app situation compared to the vast array of work in iStore or Android Market.

>>In any event if you're a MS shop it would seem madness to wander off into developing a possibly fringe Mac application. If it was me and the client insisted on an Ipad solution I'd simply recommend that they looked elsewhere for developers.

I suppose it depends whether this involves the OP's own existing niche app rather than a contract development gig. If it's for your own app you can't exactly send the customer packing. You could insist on using Silverlight which would earn praise from MS. But the customer may have very good reasons to prefer a more prevalent device (such as all the good stuff at the online app stores) and it won't be difficult for them to find somebody else who will meet their needs.