I would be interested to know too. Also, Sarmento, you say it doesn't overload the front end of your 7600GR, which is an issue for me with my PL-380. How close are you geographically to your local blowtorches?
I've had my PL-380 for probably several months now. I've noticed that in rural areas (or places where there is no strong signal nearby), the RSSI will be 15dBu when tuned to a frequency on which no station is received. I've even had the RSSI stay at 15dBu, or maybe climb a little to 17dBu, even when a station was strong enough to indicate a SNR of around 17 to 22dB.

Where I live, I have a 5kW IBOC local on 600 kHz about 8 miles west, a 77kW (50kW night) on 690 that's 32 miles south/southwest, a 5kW (50kW night) on 760 that's 7 miles north/northwest, a 5kW on 910 that's 9 miles north, a 10kW on 1130 that's 6 miles north, a 50kW (2.9kW) on 1170 that diplexes with 910, and a 5kW (1kW night) on 1360 that's 8 miles west, along with numerous other weaker signals. The typical RSSI on my PL-380 averages about 30dBu on "blank" channels throughout most of the band, although in the 1100s it will rise to around 41 or 45dBu on, say, 1150 for example. At night, I get 41dBu readings on 747 and 774kHz (on either side of 50kW blowtorch 760), the frequencies of two Japanese TPs, although I've never heard those stations.
Also, my grandparents in San Gabriel, CA, are about 1/3 mile from a 23kW on 1300 and a 50kW on 1430, and 5 miles from a 50kW IBOC on 1110. Last time I was there, the RSSI in the blank channels was 50dBu across almost the entire upper half of the band, and many local stations that should have had a good signal, like 1230, 1260, 1280, 1330, 1390, 1460, etc, were almost unreadable.

I also have another radio which is ultralight-sized and priced, although is not recognized as an ultralight due to the fact that it had already been discontinued several years before the ultralightdx definitions came into existence, and that is the Panasonic RQ-SW20. Before I got my PL-380, I also briefly bought the Sony SRF-M37W, then promptly returned it due to its horrid selectivity. I noted that my Panasonic's selectivity was comparable to that of the Sony I just mentioned.

Several weeks ago, I took my two radios (RQ-SW20 and PL-380) near the transmitter site of a semi-local station, 1kW 1450 KFSD. From about 20 meters from their tower, I compared the reception of several stations on the two radios, and what I learned surprised me. In spite of its worse overall selectivity, it appears that the Panasonic has much better front-end selectivity than the PL-380. There were several moderately readable stations on the RQ-SW20 that were completely unreadable on the PL-380. Examples can be heard at: http://cid-6bdd1917662288cb.office.live.com/browse.aspx/AM%20radio%20files/PL-380%20vs%20RQ-SW20%20comparisons/near%20KFSD%201450%20transmitter
This was in spite of the fact that the PL-380 is normally at least several dB more sensitive than the PL-380, for example locally there's a station on 980 that, while it is weak and kind-of hiding under a 30dBu noise floor on the PL-380, is just about completely unreadable on the RQ-SW20.

Also, I have a Select-A-Tenna, and while it has done fairly well with some things, including enabling me to hear 700 KALL North Salt Lake City in the daytime from about 625 miles away, I still would like something more selective and sensitive. So what's the performance of your ultralight ferrite loop like when used with your PL-380, compared to just the stock barefoot PL-380?