I'm in the process of building an EDLC based flashlight. I've purchased a cheapish XP-G R5 pocket torch that will accept anywhere from 3 down to 0.8 volts (important since capacitors voltage decreases across their entire range as they drain, unlike electrochemical cells which tend to have relatively flat discharge profiles) from one AA (or 14500) sized cell. I'm going to take the head and tale cap (all the LED, boost and regulator electronics, switch, reflector) from this torch. The EDLC I've chosen is a 3000 farad, 2.7V 'BoostCap' - this is about the size of a coke can and stores slightly more energy than a good NiMH AA cell. This SHOULD give me a run time of ~1 hour at ~160LM or 2.5 at 70LM and much longer in the ultra-low mode. The charger is actually a high power LED driver board which has ajustable voltage (which I will set to 2.68V) and output current limiter (I will set this to 5A). This is needed since 1) The EDLC will be damaged if exposed to too high voltage and I don't want to have to bee fussy about input voltages for charging. 2) The EDLC has extremely low internal resistance, without a current limiter of some sort it essentially acts as a short and would damage my internal wiring and any charger used. I can then charge it from any DC power source in the range 4 - 35V (any car, usb port, my 12v hand generator, etc).
The reason I'm building this:
1) To play with EDLC technology - the main reason i just interest and because I can
2) Near infinite rechargability.
3) Extreme cold resistance.
4) Rapid charge times - limited by power supply and my current limiter settings. With a carefully designed system could charge to 90% in a few seconds.
Drawbacks:
1) Size. The energy density of EDLCs is still a lot lower than electrochemical cells. I will end up with single AA performance from a flash light that won't fit in even my biggest pockets.
2) Cost. The EDLC, charge circuitry add a lot of cost. Approx cost EDLC £50 vs good NiMH £1.5 each.
Another fun application and something I might try in the future is very short run time, ultra high output. EDLCs can generally sustain extraordinarily high current drain. The 3KF 2.7v cap I'm using can output over 3KW - just try that safely with lithium cells. Couple some EDLCs with a ultra high output lamp and you could get many thousands of lumens in a surprisingly small unit - as long as you don't mind it only running for a few seconds.
This might not help answer your question, but thought you might be interested in an example application of EDLCs and LED technology. My guess is your best bet for decorative stuff is electrochemical cells. To get equivalent run time an EDLC needs to be many times bigger. The only real advantage for your needs would be if you plan to charge cycle it VERY often and don't want to ever have to replace the rechargeable battery.