I used Lotus about 8 or 9 years ago and if I remember correctly, it had a scripting language. Since TD's backup download is XML, it should be possible to write a macro to import/export it. Now, depending on your coding ability, that might mean employing someone to do it, but it might be worth it.
Since Toodledo uses ical import/export. I guess it would be possible to sync with Lotus Notes. I use eProductivity for Lotus Notes and keep my Errands, @Online,@Phone, @HOme tasks in Toodledo (because I am not likely to switch on my computer just to access these tasks. So far it works quite well. Those who do not have eProductivity, can directly use Lotus Notes todos.