Those are all good suggestions David and not a whole lot to add. I know Rosalva as Trepanol or Decylenic alchohol it is made by IFF but I buy mine from Hekserij, the others are widely available other than the Rosascene which I dont have or know. You probably also want some Eugenol, Linalool, Nerol and a little Citral - again all widely available.
Another material you could consider would be rose oxide, which is in Bulgarian rose otto and, curiously, also in Gewurtztraminer wine, which was what caused me to buy some.
Looking at the Rose Base in my Curtis & Williams
, they also suggest C11 enic, C8 and C12 lauric and I can see that including the aldehydes would help make it more sharp and metallic, the C12 in particular.
As modifiers they suggest iso-Butyle phenyl acetate, Phenylpropyl alcohol, Geranyl butyrate, Phenylethyl butyrate and Trichloromethylphenylcarbinyl acetate. However Ive not tried any of those in a rose accord myself.
Other options include pre-made rose bases, such as Dorina SA E or Rose Givco 217. Perfumers Apprentice
has this Rose Accord on offer (either pre-made or you can make your own from their formula):
Peonile - 40
dimethyl Benzyl Carbinyl Acetate - 30
Geranyl Acetate - 25
Phenyl Ethyl Phenyl Acetate - 20
Citronellol - 20
Undecavertol - 6
Phenyl Ethyl Acetate - 5
Rose Oxide - 3
Damascone Delta - 2
and I dont think Id have come up with Peonile if I hadnt just looked that up, so thats a bit of learning for me too.