I made 40 of each glyph type before 4.0 hit (with the exception of some charred glyphs). Some of these are now down around the 20 glyphs level, others have not sold at all, and this is fine. I missed out on much of the first mad rush of Glyphmas due to patching issues, stuffing up with pre-posting, and stuffing up using the armory AH. Small change in comparison to some others, but still more than worth doing.
With all of that, I still am doing OK. I got some of the spike, and am still making about 1.2-1.5k (and rising) / day in glyph sales, and I am thinking about how/when to restock.
On my server, Ink of the Sea (Iots) is sitting around 13g ea, Snowfall 6g ea. Lower value northrend herbs can be picked up for about 30g/stack. Back of a napkin maths says a stack cheap herbs make 5 Iots, and 0.5 Snowfall (caveat emptor - I dont do a lot of ink making), making 5 * 13 + 0.5 * 6 = approx 65g. Ink making seems profitable.
A lot of inks are being made as shown by the pitiful price of snowfall ink (used to be 12g).
A standard glyph - taking 3 inks + 1 parchment - call it 40g in cost, selling for 25g+ means that making glyphs from ink is a bad deal. Making them from herbs will still cost 18g means that 25g glyphs are marginal, and you may be better of with stopping at inks. However, 40g+ glyphs are worth making, and I will restock all of these as needed. Have a look at Breevok's explanation of type 1 (vendor taught) & type 2 (research based) glyphs. I think there is a further breakdown - those glyphs that were 'best in slot' (and therefore don't need to be re-bought), and those that have been re-worked into 'better' glyphs.
Most glyphs are not worth making yet being sold in huge quantities, and more than just levelling glyphs, ergo stockpiles are being consumed; most likely because players believe that glyphs won't be 'sellable'.
My predictions on the cost of inks between now and just before the Cataclysm:
- Type 2 (reasearch based) glyphs will recover in prices, especially those that were not previously best in slot
- Type 1 (vendor based) glyphs will fall way below replacement cost as all the part time scribes dump stock, especially where these glyphs were 'best in slot'
- Herb prices will largely stay where they are, with both more supply and demaind; rising in the fortnight before cataclysm
- Ink prices will be server dependant. They should fall based on herb prices where you have enough goblins in the market. If not, they will rise to re-crafting of glyph prices.