There is no such thing as a digital Slingbox, in fact most of the new ones are analog. I assume what you actually mean is that you have been using a Pro-HD with the built-in analog tuner ? If so, are you sure it won't continue to work ? The Pro-HD models differed a bit but some had both analog and digital tuners. You could try re-configuring it and see if it gives you the option.
Otherwise, anything with a built-in tuner that has a coax input and a composite (Yellow/Red/White) would do. Many people still have an old VCR up in the attic ?
i have had a slingbox for several years. this month our local cable company is going all digital and my slingbox will no longer work. i understand that. i went to best buy to purchase a new 'digital' slingbox. i have a problem with that. our cable that comes into the house is still through a coax cable. the new digital box does not have a coax connection. what kind of adapter can I purchase in order to be able to use the new digital slingbox with our coax cable?