Basically, if someone if willing to commit to double the dollar amount of particular sponsorship level over a multiyear period, they would qualify for that sponsorship level for the duration of the multiyear commitment.
Using myself as an example, assuming we are looking to get recognized at the minimum sponsorship level of Bronze, we would need to make a commitment to donate 2 x the bronze level. ($2k x 2 = $4k) over a multiyear time period. In our case we would commit $4000 over an 8 year period, to get recognized as a bronze level sponsor for the eight year period. (Or something like that).
The benefits to DebConf, is it starts moving revenue streams towards recurring revenue, which will aid in planning future budgets, in addition to getting larger overall commitments for the same level. e.g. - $4k instead of $2k. It also gives the sponsorship team the ability to upsell not just dollar amounts to get to the next level, but also upsell multiyear commitments. For example, if we had someone willing to commit to a $2k bronze sponsorship, you could tell them they could get silver recognition if they committed to a 5 year commitment at $2k/year.
For this to work, the levels would have to be fixed year to year. eg: Bronze needs to stay at $2k. We (Debian) would also need it to be a bit more formalized than just a sayso on IRC. (IE: A formal donation form/commitment would need to be required.) In addition, only current and future commitments would count here. (not past donations.) This wouldn't mix with local sponsorshp levels, which are variable, and really don't fit. I would also say that the ratio of annual commitment can't really be longer than a fixed period of time, e.g. - One can't say "I commit to $500 a year over the next 100 years to get the highest level."
Thoughts? (I haven't fully fleshed it out, and imagine there are some drawbacks that I haven't fully thought out.)
Cheers,
Brian