I recently used a Google offline map on my iPad while in BWCA. Worked great, but the Google maps have very littile detail. Are there other electronic maps offered by software vendors that would have more detail, even showing lake depths? Or, has anyone figured out how to download satellite view for offline viewing?

Sound like a question for superman...errr. .. Super butthead.

You can cache satellite images in the Google Earth app. I believe the cache clears out after a year or so. I did this before my trip to the Sutton river, and it worked fairly well.

There is an app called 'Backcountry Navigator' that you can download USGS topos to for navigation. I use this with the gps built into my phone, and its a good solution. For Canadian trips there is an app called 'Canada Maps' that is essentially the same thing, although you won't get lake depths in most areas. For both of these apps, you obviously have to pro-actively download the maps for the area you are travelling in advance of your trip.

Navionics has a nice app that includes depth soundings of many lakes.