It may be interesting for you that I did some quite accurate triode LTspice models, especially regarding grid current.
More or less similar (in terms of mu) to what you request are the following of my models:
Sylvania 6948
RFT ECC81
electro-harmonics 12AT7EHG
You will find a zip of my models here:
http://adrianimmler.simplesite.com/440956786
The code of the last two models is also visible here:
Vacuum Tube SPICE Models
Thank you Adrian. Look very interesting. Have try out your models.