I guess I will second Steve's comment.
It's great that RadEditor automatically detects the iPad/iPhone and adjusts but it's not really a complete solution if the API changes in the process.
I still really appreciate the quick response. ... I will attempt the workaround for now.
UPDATE: When the RadEditor is in "ipad" mode, an attached RadSpell fails as well.
<telerik:RadSpell ID="RadSpell1" runat="server" ControlToCheck="RadEditor1"
What a pain. (And I blame the iPad / iPhone for causing the extra work)