What happened to vhdl.org?

Afaik, the 2008 libraries are only included in prime pro - otherwise you have to provide the code as part of your project. But quartus has worked just fine with the compatability packages since at least 2009, where I was using it to infer multipliers and rams from ufixed and sfixed.

Using numeric_std is actually the "normal" way to do it. fixed_pkg actually re-invents the wheel and is hardly used. numeric_std has been around since 1993 and has arithmatic, resize() etc. But yes, you have to track the integer/fraction separation yourself, but it's not that hard to do - it just takes a little thinking. And to be fair, if you ever have to use the altera lpm library (for a divider for example), you'll have to convert everything to slv anyway.