I do not know of such a beast with a countersunk head.
Whatever there is, it's likely to be rare and costly.
Have you searched ASSIST with the appropriate terms?
Only one I know of: the series of bolts from NAS6603 to NAS6620 have a 1/64" oversize. Not applicable but it may help your search.

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF

Miner89r...

The NAS 6-lobe recess fastener specs [obviously] do not include over-sizes [X][Y] like many other specs.

However, other than the recess, this is a typical FTH Bolt with long threads, in either CRES or Titanium alloy [95-KSI-Shear, 160-KSI tensile], W/WO a patch locking element.

Possible OS Replacements... my order of preference... may/may-not be readily available [special order]

NOTE.
There are similar-to bolts with corporate part numbers... but I'm sticking with NAS equivalents

A286 CRES replacements
NAS7203-7216... Nom, 1OS [X] and 2OS [Y] [cruciform recess drive]
NAS1790C... Nom, 1OS [X] and 2OS [Y] [Dovetail or off-set-cruciform recess drive]
NAS1580C... Nom, 1OS [X] and 2OS [Y] [Dovetail or off-set-cruciform recess drive]
HT4026C... Nom, 1OS [X] and 2OS [Y] [Dovetail recess drive]

Titanium replacements
NAS7303-7316... Nom, 1OS [X] and 2OS [Y] [cruciform recess drive]
NAS1790V... Nom, 1OS [X] and 2OS [Y] [Dovetail or off-set-cruciform recess drive]
NAS1580V... Nom, 1OS [X] and 2OS [Y] [Dovetail or off-set-cruciform recess drive]
HT4026V... Nom, 1OS [X] and 2OS [Y] [Dovetail recess drive]

Low alloy steel replacements [if applicable]...
NAS7103-7116... Nom, 1OS [X] and 2OS [Y] [cruciform recess drive]
NAS1790... Nom, 1OS [X] and 2OS [Y] [Dovetail or off-set-cruciform recess drive]
NAS1580A... Nom, 1OS [X] and 2OS [Y] [Dovetail or off-set-cruciform recess drive]
HT4026... Nom, 1OS [X] and 2OS [Y] [Dovetail recess drive]

NOTE.
IF FTH, short thread, Bolts are permissible then may consider...
NAS7400-7416 [LA Steel]
NAS7500-7516 [A286]
NAS7600-7616 [Titanium]

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

Wow, Thanks Will just what I needed.