There are only three other OTC places I know (besides hydro stores) which routinely deal in H2O2 in that concentration.

Those places are:

-Beauty stores/salons
-Janitorial supply houses
-Restaurant supply houses

I can't comment on whether it is stabilized or not.

I should warn you about the beauty supply stores - a year or so ago, there was a terrorist incident involving some moron who went around to several beauty stores buying up the concentrated H2O2 for an acetone peroxide bomb. Fear leaflets and information campaigns ensued among the salon industry, and several manufacturers promised to reformulate. Keep that in mind and use suitable discretion when shopping around - probably not a good idea for anybody to show up and head straight to the concentrated H2O2, study the label, then exit with an amount appropriate for synthesis - especially if you fit the chemist profile (nerdy, male, probably not style obsessed) rather than the salon customer profile.

I'd start scouring the cleaning supply places. Everybody is on a green kick lately, so H2O2 is fairly innocent there.

You could stabilize it yourself with the appropriate agent: http://www.h2o2.com/faqs/FaqDetail.aspx?fId=11

The local hydro stores are a hit and miss when it comes to H2O2. Be careful of bad stock which is either old or improperly stored. Not all hydro stores are selling crap. Maybe look for a manufacture date on the container?

Online orders will be prohibitively expensive. 8% (IIRC) is the hazmat threshold on H2O2.

jon, tried freezing it in my freezer and it it wouldn't solidify even over night.  I don't really feel like dealing with a dry ice/acetone bath.  At that point I might as well vacuum distill

OxyClean and similar detergents use a complex called sodium percarbonate:

http://its.goofyti.me/u/http://en.wikipedia.org/wiki/Sodium_percarbonate

which looks to be just H2O2 bound to sodium carbonate. Is it possible to recover some or all of the H2O2 from this? It seems like using a solvent which dissolves H2O2 but not Na2CO3, like ethanol, would at least get a reasonable amount of H2O2.

Wiki even mentions it as "a laboratory source of anhydrous hydrogen peroxide". Sounds quite promising!

I don't think it is worth the time to get H2O2 from such cleaners - I've looked into that a bit, and it seems like it has some serious issues with pH and other things that like to destroy H2O2.
Would love to see differently though! Pretty sure there is a thread about this over at SM, though, its probably inconclusive.

https://www.sciencemadness.org/whisper/viewthread.php?tid=971

one of a few

Just like to note that 15% H2O2 works just fine in the performic, just adjust accordingly. 72% molar yield is possible (assuming the starting material was pure isosafrole, which is unlikely)

you may just have to resort to buying it on-line, yeah, the shipping is expensive, but the quality is awesome. I can't think of anyplace that has it other than on-line.

There's no bleach blondes or dry ice anywhere around there   Hydrogen peroxide is easily concentrated a many ways; including distillation, freezing and sparging  

h**ps://secure.wikimedia.org/wikipedia/en/wiki/Sparging_%28chemistry%29

In the case of concentrating hydrogen peroxide, warm dry air is bubbled through a solution 

There's not much information available on the internet:

h**p://www.all-science-fair-projects.com/science_fair_projects_encyclopedia/Sparging

h**p://www.all-science-fair-projects.com/science_fair_projects_encyclopedia/H2O2

except for junior high science students