Loglan and Lojban give entirely too much weight to Chinese and other large languages (in terms of numbers of speakers) that have zero relationship to IE (unless you're heavily into Nostratic). I'd like to see someone combine an exemplary form of Romance languages (like, Latin or early French) with an exemplary form of Germanic languages (like modern Icelandic or reconstructed proto-Germanic) to form a new lingua franca [insert corresponding Germanic term here] for use among language enthusiasts in Europe. Call it Frankenlingua ?