We would be lucky to even get 10,000 supporters.
And if these people are doing a "bargain" for "only" 390 euro for just the board, then I say no dice.

A better choice would be to build an actual (high-end) phone from scratch and port Maemo/Mer to it.

An even better one would be to get a pre-existing model and port to that device. Perhaps if a collection was gathered for like $2-3M ...then a handful of talents could be hired to work full-time with open invitation for other devs to contribute.

Perhaps, they could select the device... maybe something that would be easier to port to because of available documentation and found on several devices.

That way, although they could target a single device... there efforts could potentially be used to make quick ports to similar devices eg/
- Target: Galaxy S4
- SoC: QSD 600
- Other "sibling" devices: SGS4 Active, HTC One, Optimus G PRO, Xiaomi Mi-2S, New Nexus 7, Oppo N1
- Similar Specs: QSD 800, QSD 400, QSD S4 Pro
- Similar Spec devices = Xperia Z, Xperia ZL, LG G2, Optimus G, HTC One Max, HTC One Mini, SGS4 Mini, Galaxy Mega 6.3, Nexus 4, Moto X, Oppo Find 5, Pantech Vega 6

Perhaps it could be something along the lines of:
$1 or more gets you a "Thank You"
$50 allows installation
$80 installation and T-shirt
$100 installation and exclusive developer access
$150 installation, dev access, permanent name in credits on website and software
$200 installation, dev access, credits, keyboard accessory
$800 phone with pre-installed software, engraving, accessory, dev access, credits, TV shirt

...the project could even strike support from the likes of Samsung, HTC, or Qualcomm.